In the past, oven designs of many types have been in use for a variety of purposes. Typically, these have been insulated enclosures with the ability to add heat through a heating element or other heat source. Some of these designs have employed fans to circulate the air internally. Others, particularly those used for heating semiconductor wafers, employ a feature of evacuation of the oven prior to release of preheated nitrogen into the oven. Such application is shown in U.S. Pat. No. 4,597,736. Other types of ovens which illustrate the use of heating elements and fans are U.S. Pat. Nos. 5,185,126; 4,460,332; 3,353,805; 3,958,936; and 2,504,810. U.S. Pat. No. 4,699,119 illustrates a heating cabinet which is portable for use in warming drums. A steam coil is provided along the bottom, below a support grating for the drums. A catch basin is provided in the enclosure which is open through the wall of the oven to provide not only drainage but also an outlet for any pressure that may accumulate within the enclosure.
These prior designs do not address unique situations involving highly viscous fluids which can emit flammable vapors when sufficiently heated to reduce their viscosity to a point where they can be easily pumped for further use in other processes. What has been lacking in prior art is a simply designed oven which takes into account the need to simultaneously warm, agitate and pump out containers such as drums while they are being heated, while at the same time paying particular attention to the safety aspects involved in dealing with vapors that can be emitted during the warming procedure.